The present invention relates to an arrangement of cooling holes in an aerofoil of a gas turbine engine.
Gas turbine blades and vanes, particularly those in the hot turbines, may require cooling and it is well known to provide a coolant flow to an internal passage of the component. Holes are provided through walls of the component so that the coolant removes heat from the wall and may form a coolant film over an external surface of the component.
U.S. Pat. No. 5,062,768 discloses a turbine blade having a wall defining multiple angled cooling holes that intersect and have a single exit. Where the holes intersect there is a constriction. This arrangement is characterised in that the cross-sectional area of flow for the coolant is greater at the exit than at the intersection, thereby avoiding blockages at the exit.
U.S. Pat. No. 5,370,499 discloses a turbine aerofoil wall having a mesh cooling hole arrangement which includes first and second pluralities of cooling holes between internal and external surfaces. The cooling holes of each plurality extend generally parallel to one another and intersect leaving internal nodes. Coolant jets interact with one another at these intersections and cause a restriction of the flow, thereby producing a pressure drop. The area of the flow inlets is substantially less than the area of the flow outlets.